The present invention relates generally to a motor grader, and more particularly, to an apparatus and method for retaining a grader blade.
Motor graders are typically used to perform displacement, distribution and leveling of material, such as soil. Generally, a motor grader includes a tractor unit coupled to a grader group via a tow bar assembly. The grader group includes a blade assembly having a grader blade, as well as a mounting assembly having a support bracket with retainers extending therefrom. The blade assembly is positioned in the retainers such that the grader blade is supported by the support bracket. Wear strips are provided between the retainers and the blade assembly to facilitate the retention of the grader blade in the assembly, while allowing sliding movement of the blade assembly with respect to the retainers. The tractor unit moves the blade assembly over the ground, so that the grader blade engages with the material, such as soil, so as to displace, distribute or level the soil.
During use of the motor grader, the grader blade is tipped and sideshifted, to manipulate the material as discussed above. The wear strips tend to erode during use, thus loosening the retention of the grader blade so that there is unintended motion between the grader blade and support bracket. A loose grader blade inhibits the accurate displacement, distribution and leveling of the material.
To overcome this problem, shims are installed to fill any horizontal gaps caused by the erosion of the wear strips. However, using shims is work intensive, and thus increases the maintenance cost of the motor grader. Moreover, the insertion of shims only inhibits, and does not effectively stop, the unintended motion between the grader blade and the support bracket.
U.S. Pat. No. 5,687,800 provides a retaining apparatus in which the necessity of shims is reduced. In particular, a retaining apparatus having a turnbuckle mechanism facilitates the tightening of the fit between the retainers and the blade assembly as the wear strips erode. However, the turnbuckle mechanism is complex. In addition, the turnbuckle mechanism only allows for a limited movement of the retainers with respect to each other, and thus, the method for assembling the blade assembly to the mounting assembly is cumbersome because the blade assembly must be slid sideways into the retainers. Also, the wear strips must be aligned between the retainer and the blade assembly. The present invention is intended to overcome these and other problems of conventional motor grader retention systems, by providing a retaining system in which the mechanism for adjusting the fit of the retainers is simple, the wear strips are self-aligning, and the method for assembling the blade assembly to the mounting assembly is efficient.
According to a first aspect of the invention, a mounting assembly for mounting a blade assembly to a motor grader, is provided with an upper and lower retainer pivotally coupled together, wherein the upper and lower retainers are pivotable about a single axis with respect to each other for grasping the blade assembly therebetween.
According to a second aspect of the invention, a wear strip for mounting a blade assembly to a mounting assembly of a motor grader includes a member having a flat inner surface and a curved outer surface, wherein the curved outer surface mates with the mounting assembly and the flat inner surface mates with the blade assembly.
According to a third aspect of the invention, a method for assembling a mounting assembly to upper and lower blade rails of a blade assembly is provided. The mounting assembly includes upper and lower retainers pivotally coupled together, and self-aligning wear strips. The method includes the steps of pivoting the upper and lower retainers away from each other, placing the upper retainer over the upper blade rail and placing the lower retainer under the lower blade rail, and pivoting the upper and lower retainers toward each other until the upper and lower blade rails are securely fitted to the upper and lower retainers with the self-aligning wear strips disposed therebetween.